In the literature, there are various described methods to obtain hallux valgus correction of the first metatarsal or bunion correction. A bunion or “hallux valgus” or “hallux abducto-valgus” are the most commonly used medical terms associated with a bunion anomaly, where “hallux” refers to the great toe, “valgus” refers to the abnormal angulation of the great toe commonly associated with bunion anomalies, and “abductus/-o” refers to the abnormal drifting or inward leaning of the great toe towards the second toe, which is also commonly associated with bunions. “Hallux abducto” refers to the motion the great toe moves away from the body's midline.
Three of many commonly performed procedures to correct bunion or a hallux valgus deformity in the foot are discussed below.
A scarf, or z-osteotomy, was described by Meyer (1926) and Burutaran (1976) and used experimentally for hallux valgus correction by Dr. Charles Gudas in 1984, who used a Z-cut osteotomy of the first metatarsal to gain correction of the metatarsus primus varus and bunion deformity. The word scarf is a term used in carpentry (an architectural term) to describe the notching or cutting of two pieces of wood so that they interlock and form a strong bond. This notching technique is the basis of the scarf osteotomy procedure. In this procedure, the long bone, or metatarsal, of the first toe is sliced horizontally and two transverse cuts or notches are made at each end of the bone. The lower piece of the first metatarsal is moved inward to reduce the angle between the first and second metatarsals and bring the toes closer together.
The scarf osteotomy is a medial, longitudinal osteotomy cut that combines two transverse cuts at each end of the longitudinal osteotomy cut. The scarf osteotomy has gained popularity in Europe in recent years because it is versatile due to its tri-planar configuration, allowing correction of the IMA (intermetatarsal angle) and DMAA (distal metatarsal articular angle) simultaneously through translation and rotation.
A scarf osteotomy surgical procedure entails making a dorsal/medial skin incision extending from the first metatarsal phalangeal joint to the base of the first metatarsal joint. Once exposure is obtained, an osteotomy is performed which cuts the metatarsal bone. There are two components to the scarf osteotomy. A longitudinal osteotomy cut is then followed by two transverse cuts. The longitudinal osteotomy cut varies from 25-40 mm long depending on the length of the metatarsal and amount of hallux valgus correction required. The transverse osteotomy cuts are made at the distal and proximal ends of the longitudinal osteotomy cut and the transverse cuts vary from 25 to 90 degrees in relation to the longitudinal osteotomy cut. There are variations on the osteotomy cut, but they essentially follow the same longitudinal osteotomy cut and 2 transverse cuts.
After removal by a medical saw blade of the medial eminence of the metatarsal head or bump on the metatarsal head, the first component of the scarf longitudinal osteotomy cut starts about 3 mm to 4 mm below the dorsal/top medial surface of the metatarsal head and approximately 5 mm proximal to the articular surface of the first metatarsal. The scarf longitudinal osteotomy cut continues down the long axis of the metatarsal bone, parallel to the proximal medial border and continuing plantarward so that it reaches the lateral surface approximately 3-5 mm dorsal of the plantar cortex, ending approximately 20 mm distal from the metatarsal-cuneiform joint articulation. The longitudinal osteotomy cut runs parallel to the plantar surface, about 3 mm to 4 mm above the plantar cortex of the metatarsal. The second component of the scarf osteotomy is the transverse osteotomy bone cuts. They are approximately made at 25-90 degree angles in relation to the longitudinal osteotomy cut, forming proximal and distal “chevron like” osteotomy cuts. The distal/dorsal transverse osteotomy cut is approximately 5 mm proximal to the margin of the dorsal cartilage and at an approximate angle of 25-90 degrees to the longitudinal osteotomy cut and is made from dorsal to plantar. The proximal/plantar transverse osteotomy cut is approximately 20 mm distal to the articular surface of the base of the metatarsal and is angled out the plantar cortex through the metatarsal bone at approximately a 45 to 60 degree angle to the longitudinal osteotomy cut and is made from plantar to dorsal.
Once the scarf osteotomy is completed, the section of the plantar metatarsal bone is gently pulled laterally and the section of the dorsal metatarsal bone is gently pulled medially to allow for appropriate hallux valgus correction of the metatarsal bone.
The scarf osteotomy is an intrinsically stable osteotomy cut but under weight or load bearing conditions may cause stress risers or fractures dorsally across the metatarsal shelf from the proximal plantar osteotomy. The scarf osteotomy also presents the possibility of “troughing” of the two halves of the metatarsal bone which happens when the cortices wedge into the softer cancellous bone of the metatarsal shaft. This causes a functional elevation or dorsiflexion of the first metatarsal that may lead to a pronated foot and lesser metatarsal bone overload.
Scarf osteotomies have been previously fixated with K-wires and screws, but most notably always 2 or 3 screws. The fixation techniques reported vary in steps, screw diameter sizes used, k-wire sizes used, placement, etc.
The Ludloff osteotomy was first described in 1918 and is a through and through osteotomy in the transverse plane extending dorsal-proximal to plantar-distal when viewed in the sagittal plane (from the side). The Ludloff osteotomy allows for intermetatarsal angle reduction, lengthening, and plantar displacement. The osteotomy is not intrinsically stable, and therefore strong fixation is necessary.
A Ludloff osteotomy surgical procedure entails making a dorsomedial incision over the first metatarsal of the foot which extends from the first metatarsal phalangeal joint distally to the base of the first metatarsal joint proximally. Once exposure is achieved, the osteotomy is performed using a standard medical surgical sawblade to cut the bone. The Ludloff osteotomy begins dorsally about 1 cm to 1.5 cm distal to the base of the first metatarsal, angled approximately 30 degrees, extending from dorsal-proximal to plantar-distal, and ends just proximal (before) to the sesamoid complex at the first metatarsal distal base. The Ludloff osteotomy cut is thorough and through for about two-thirds way through the metatarsal bone. At this point the surgeon stops the osteotomy cut and temporarily fixates the metatarsal bone at the proximal-dorsal location. This temporary fixation, before the Ludloff osteotomy is completed, allows the surgeon to rotate the metatarsal bone laterally after completing the Ludloff osteotomy cut. Temporary fixation is completed and various authors describe fixation by using kwires or screws. The Ludloff osteotomy cut is then completed and the dorsal aspect of the metatarsal bone is gently shifted laterally to obtain the desired hallux valgus correction, using the temporary fixation point located at the proximal-dorsal location as an axis point or rotation point. Lateral correction of the dorsal aspect of the metatarsal bone is performed by pulling the plantar metatarsal fragment medially and the dorsal metatarsal fragment laterally with manual pressure applied to the medial aspect of the first metatarsal head. The Ludloff osteotomy is then fixated distally with kwires or screws and the osteotomy correction is complete. Ludloff osteotomies have previously fixated with no internal fixation until reported with internal fixation of screws, kwires or a combination of screws and kwires.
The Mau osteotomy was first used in 1915 and presented by Mau in 1926. Mau modified the Ludloff osteotomy cut by changing the direction of the osteotomy cut. The ludloff osteotomy is a through-in-through, oblique diaphyseal osteotomy cut extending from dorsal proximal to plantar distal on the first metatarsal bone. Mau reversed the Ludloff cut and challenged the stability of the Ludloff osteotomy by creating a dorsal shelf to help resist weight-bearing forces. The Mau osteotomy is a through-in-through oblique diaphyseal osteotomy cut from plantar proximal to dorsal distal through the shaft of the first metatarsal.
The Mau osteotomy is made parallel to the weight bearing plane and its long dorsal shelf of bone supports the distal fragment, making dorsal displacement of the first metatarsal osteotomy cut unlikely. The Mau type osteotomy is an intrinsically stable metatarsal osteotomy cut because of the dorsal shelf that resists dorsal displacement forces. Weight bearing on the foot compresses the osteotomy.
The Mau osteotomy surgical technique is achieved with a standard medial approach incision to obtain exposure of the first metatarsal bone. After identifying the tarsometatarsal joint (TMTJ) and using a medical power saw, the oblique Mau osteotomy cut is begun about 1-2 centimeters from the first metatarsal head and made from dorsal-distal to proximal-plantar, parallel to the weight bearing surface of the first metatarsal bone. The plantar metatarsal bone fragment is then laterally rotated transversely and realigned to correct the desired anatomical alignment. Once appropriate realignment of the first metatarsal bone is completed to correct the hallux valgus deformity, various methods of fixation are inserted into the first metatarsal to hold the metatarsal in its realigned position.
Mau osteotomies have been previously fixated with K-wires and screws, but most notably always 2 or 3 screws. The fixation techniques reported vary in steps, screw diameter sizes used, k-wire sizes used, placement, etc.